1. Field of the Invention
The present invention relates to automobile industry, more particularly the present invention relates to cost effective, time efficient fabrication of automotive body structures.
2. State of the Art
Conventionally the body structure and other parts of vehicle like chassis are constructed by assembling, mostly through welding, various pre-formed sheet steel panels to create the body structure of the vehicle, and then bolting the body to a supporting metal framework known as the chassis. Another well known method in the state of the art is to construct the body and the chassis together as a monocoque, i.e., the body and chassis are in one piece. Although both methods produce high quality vehicles, these methods have several disadvantages. These manufacturing processes are complex and expensive. The above mentioned methods involve number of steps including the stamping of each body and chassis part and the assembling and welding of each of these parts to the others to create a complete body and chassis. Large investments are required in factory equipment and the requisite dies, apart from the logistics and the assembly line to manufacture parts of the body of the vehicle using such methods.
The manufacturing of vehicle body structure by above mentioned method requires many original equipment manufacturers (OEM) suppliers since large number of components are required to be sourced each involving the process of punching, welding, shaping, finishing and very often coloring. Such processes are often not environment friendly and involve wastage of materials by way of scrap. Such manufacturing practices also require large area in assembly line for the assembling of the parts sourced from such OEMs. Apart from the requirement of large area, the time taken for the production of the body structure is also substantially greater in the above mentioned approaches.
Further, the steel or metal body panels tend to deform and dent when struck with anything but the lightest of forces. These vehicle body structures are therefore easily damaged, resulting in high insurance and repair costs.
The other methods for production of body structure for automotive vehicle from polymeric material having an edge over the above mentioned methods with regards to number of OEMs, space required for assembly line and time taken for the manufacturing the body structure.
Over the past few years the Rotational Molding technology has been moving forward at a fast pace. The production of a small size, low cost motor vehicles is made possible by utilizing rotational molding technique. The invention proposed by way of this application realizes the opportunity to produce a one/two/three piece molding body shell that can incorporate the hinge reinforcement, latch reinforcement, instrument panel, cross car beams, seat panel moldings, seat belt anchorage points etc.
Some of the approaches known to us that have improvised plastic body for the automotive vehicles are as follows:
U.S. Pat. No. 7,287,797 filed by Belloso et al. teaches an automotive vehicle body made of interconnected plastic components including a floor module and a metal framework. The framework has elongated longitudinal and transverse structural members of uniform cross sectional configuration. The framework and body are integrated in a manner which minimizes stresses that would otherwise be conveyed to the body from the framework. Though this reference uses an automotive vehicle body of polymeric material manufactured by roto-molding process, a polymer fabrication technology, it uses significant amount of steel and metal framework as a supporting member.
U.S. Pat. No. 5,286,080 filed by Ringdal et al. teaches a method for the manufacture of plastic car bodies, preferably molded or cast in one piece, with openings for doors and windows. To make the body lightweight and as safe as possible, it is assumed according to the invention, that one uses internal roll-over safety bars and a metallic floor frame/chassis, preferably of aluminum. Though the invention proposes the use of molded or casted plastic body it does not eliminate the use of metallic floor frame (chassis) as a supporting member for plastic body structure in an automotive vehicle.
U.S. Pat. No. 6,588,785 by Monary et al. teaches a vehicle, which is specifically adapted to be used as a bumper car. The vehicle is constructed from a frame that allows the vehicle to absorb and deliver impacts in a more efficient manner. The frame is constructed from a rotationally molded impact absorbing plastic. Though the body structures discussed in '785 patent uses polymeric material for manufacturing, but to sustain the load of passengers vehicle has to remain dependent on supporting metal structures like chassis, sub-frame, flooring etc.
In view of the prior art, none discusses the advantages proposed by way of this patent application.